Your eXpert Guide to
Protein

High protein diets for muscle growth and strength dates back to the Olympics in Ancient Greece⁶. Protein supplements represent the most widely used sport supplement representing a billion dollar industry. 20 years ago the benefits of high protein diets were hotly debated between athletes and scientists. It is now agreed that active individuals need higher than the recommended daily allowance (RDA) for protein.

Protein makes up part of the structure of every cell and tissue in your body, including nails, hair and muscle. An average person is made from around 10-12kg protein, mainly stored in your muscle. Figure 1 shows us the important roles protein plays within our bodies.

Amino acids are the building blocks of protein. They combine in different combinations to form different proteins. When you eat a protein source, such as a chicken, it is broken down in digestion to amino acids. Once in the muscle, the amino acids reform to protein.

Protein can be found in the following foods:

Protein makes up part of the structure of every cell and tissue in your body, including nails, hair and muscle

• Meat: Beef, chicken, turkey
• Fish: Cod, mackerel, tuna
• Dairy products: Cheese, milk, yoghurt, eggs
• Nuts and seeds: Peanuts, cashew nuts, walnuts, sunflower and sesame seeds
• Pulses: Baked bean, lentils, kidney beans
• Soya products: Soya mince, tofu, soya milk

Protein supplements

Protein supplements are a convenient, inexpensive way to meet your protein needs. Protein supplements are available in:

• Protein powders
• Protein nutrition bars
• Ready-to-drinks

These products supply a concentrated sources of protein that fall somewhere between food and supplement. The problem with most protein sources in the diet is they contain high amounts of fat. Protein supplements solve this by providing high amounts of protein with minimal fat and carbohydrates¹.

The physically active need more protein in their diet to compensate for protein breakdown during and after exercise. Protein powders help you achieve optimal protein intakes. A high protein diet alone will not improve your performance without training. Research is lacking showing a direct effect of improved performance from protein but the following has been shown to:

Sub-optimal protein intakes lead to slower gains in strength and muscle mass and can even result is muscle wastage

• Enhances lifting capacity³
• Reduce post-exercise muscle breakdown following running exercise⁴
• Increase muscle mass⁵,⁷

Sub-optimal protein intakes lead to slower gains in strength and muscle mass and can even result is muscle wastage. If you are involved in the following activities you should benefit from protein supplementation:

• Strength and power training
• Long intense endurance training
• New to strength training
• Weight loss program
• Vegetarian or vegans

Athletes who train for strength and power require a higher protein intake over sedentary and endurance athletes. During and immediately after resistance training the rate of protein breakdown exceeds muscle building. For growth you must be in a state of 'positive nitrogen balance'. Consuming protein following workouts encourages new muscle growth.

Athletes who regularly train for long or intense endurance sports require increased dietary protein intake to compensate for the breakdown during exercise. After 60-90 minutes endurance training when glycogen levels are low protein can be used as an energy source.

How much?

Each individual needs different amounts of protein depending on your sport. Table 2 allows you to calculate how much protein you should be aiming for in your diet each day. Increasing your protein intake above what your body needs will not lead to increased size and strength.

Table 2 Daily protein needs

When?

There are several important times in an athlete's day to consume protein for maximum results. Firstly, your muscles need protein in the morning when they have been starved of food during the night. However, the most important time to eat protein is immediately after training. This is when protein synthesis is increased to optimize recovery and promote growth¹⁰. Using casein before bed will supply a slow release of protein throughout the night.

There are 3 main types of protein that are found in protein supplements:

• Whey protein
• Casein Protein
• Soy protein

Whey protein

Whey protein is the most popular protein supplement. Whey is extracted, isolated and refined from milk protein. It is easily digested and rapidly absorbed into your muscle making it the perfect post workout protein. There are 2 forms of whey protein; whey protein concentrate (WPC) and whey protein isolate (WPI). They can be purchased in these single forms but most protein supplements contain a blend of the two.

Casein Protein

Casein is also derived from milk protein. Casein is absorbed slowly, delivering a constant supply of amino acids to the muscles for longer. This makes casein ideal for before bed or when you know you can't eat for several hours. Casein protein provides a higher quality source of amino acids and recovery boosting glutamine than whey.

Soy Protein

Soy protein is produced from soybeans, a plant extract originally from China. Soy protein is low in fat, high in branched chain amino acids and glutamine. Isoflavones in soy play an important role in reducing breast and prostate cancers¹⁴. Soy protein contains many other beneficial nutrients including calcium, iron, potassium, Vitamin E, and fibre.

Athletes who train for strength and power require a higher protein intake over sedentary and endurance athletes

Protein powders are mixed with water or milk to make a shake. They provide an inexpensive way to increase your protein intake without the fat and carbohydrates found in whole food. Protein powders are divided into 2 main categories:

• Whey protein
• Speciality protein

Whey Protein

Whey protein is not only the most popular protein supplement but also represents the most sought after supplement. Whey protein is rapidly digested for fast absorption into your muscles. This allows for rapid recovery and growth of muscles after training.

Specialty proteins

Specialty proteins are more complex and usually contain a blend of whey, casein and soy proteins. There are usually added ingredients such as creatine, colostrum, glutamine, amino acids, vitamins and minerals. The added ingredients will further encourage muscle growth and recovery.

Protein bars provide the ultimate convenience combining high protein content in a tasty bar. They are ideal for using on the go when you can't get to a shaker or blender. Protein bars supply you with quality whey protein or protein blend to help you maximise your protein intake. Protein bars are more filling than the powders and also contain more carbohydrates and fat.

Protein ready to drinks are pre mixed protein drinks. They are designed for convenience to take on the go or to the gym. Like protein powders, RTD's provide a high protein source with limited carbohydrates and fat. They provide the highest amounts of protein but are more costly than bars or powders.

Table 2: Comparison of average nutritional values for protein supplements

Once you have met your protein needs, consuming additional protein will not convert into muscle mass. Therefore too much protein will have no additional benefits on health or performance.

It was previously thought that excess protein consumption caused liver and kidney damage. This was due to the additional stress on these organs but there has been no research to support this. Those with pre-existing liver and kidney problems are advised to follow a low protein diet.

Following a high protein diet can cause dehydration, this can be avoided by making sure you drink plenty of water.

I am a Vegetarian is protein supplementation ok for me?

Yes. As a vegetarian or more specifically lacto-vegetarian maintaining your daily protein intake through non-meat sources can be challenging. However through the addition of supplementary milk-based proteins your total intake can be vastly improved.

What is colostrum?

Colostrum is the milk produced by cows in the first days after giving birth. Colostrum is rich in immune boosting nutrients and is known for its muscle building properties. Research studies have shown colostrum to be beneficial in improving performance in a variety of sports including running, cycling and hockey⁹

What's a fast and slow protein?

The concept of slow and fast relates to the rate at which proteins are broken down and absorbed⁸. Whey protein are fast protein and casein is a slow protein. Whey is easily broken down to pass into the blood stream and skeletal muscle rapidly. Casein has the ability to clot and therefore takes a longer time for absorption for a slower release of peptides and amino acids¹⁰

What is 'nitrogen-balance' and how is it related to protein?

Nitrogen balance is a measurement to estimate the difference between nitrogen intake and output in the body. This enables you to measure protein sufficiently. In a state of 'positive nitrogen-balance' you are consuming more protein than you excrete. This positive environment stimulates muscle growth. If you limit your protein intake you may then fall into a negative nitrogen-balance which will lead to muscle catabolism¹¹